1. Field of the Invention
This invention relates to multi-spectral detectors of luminescence, and in particular to the detection of luminescence from materials that are stimulated with light sources.
2. Background of the Invention
Multi-spectral detector systems may detect luminescence from particles and materials that are stimulated with a light source. Such systems may further analyze the luminescence. Multi-spectral systems may include a flow cytometry system that characterizes and classifies particles of interest from heterogeneous populations. Flow cytometry interrogates a particle suspended within a stream of liquid as the particle passes through a light focusing on a small region. Early flow cytometers measured only light scatter and Coulter volume with minimal ability to measure fluorescence. Later, flow cytometers began to collect the fluorescence emission of light in the visible spectrum that might represent the presence of various chemical or biological components. The flow cytometers analyze single micro-particles and/or cells, separating the micro-particles and/or cells into populations based upon statistical differences of intensity measurements from each particle/cell.
Single-cell detection systems use screening devices that detect light emitted by a particle after its excitation by a light source and split the light into different pathways according to the wavelengths via filters. The number of photons, which relates to the intensity of the luminescence, for each wavelength range can be detected by a detector from which the electronic signal is passed through a variety of circuits and may be presented as a data set saved in memory. This detection process is based on the evaluation of signal intensity in a single optical band; therefore, without signal separation, it is difficult to identify the nature of the component. The fluorescence emission of almost all organic fluorochromes is broad, making it difficult to measure the emission intensity of an individual fluorescence label to the exclusion of another. This is the ultimate limitation of current systems. Accordingly, there is a need for a system that provides a spectral signature of the luminescent emission from particles and materials.